1 class Solution {
2 public:
3 ListNode* deleteDuplication(ListNode* pHead)
4 {
5 if(pHead == NULL || pHead->next == NULL)
6 return pHead;
7 ListNode *head = NULL, *pb = pHead, *pe = pHead->next, *pre = head;
8 while(pb && pe)
9 {
10 while(pe && pb->val == pe->val)
11 {
12 pe = pe->next;
13 if(!pe)
14 {
15 if(pre)
16 pre->next = NULL;
17 return head;
18 }
19 else if(pb->val != pe->val)
20 {
21 pb = pe;
22 pe = pe->next;
23 // if(!pe)
24 // return head;
25 }
26 }
27 if(pre != NULL)
28 {
29 pre->next = pb;
30 pre = pb;
31 pb = pe;
32 if(pe)
33 pe =pe->next;
34 }
35 else
36 {
37 head = pb;
38 pre = head;
39 pb = pe;
40 if(pe)
41 pe = pe->next;
42
43 }
44
45 }
46 return head;
47 }
48 };
